I have a Dell 2407wfp and I'm trying to send it 1920x1080 (native is 1920x1200) from my NVidia FX4500sdi. I can feed the display this res using video devices like DVD players or Video playback machines and the DFP image just leaves 60 pixels at the top and bottom black. But I can't get the NV driver to send this signal at all... it always logs :

OK thanks lonni !
I've attached the Xorg.0.log. I did notice now that X is checking the EDID of the LCD even though I've attempted to tell it not to in several ways - seems odd.

More importantly, the log notes that 1920x1080 is > than the max 170Mhz EDID freq. However 1920x1200 = 154Mhz. Shouldn't the smaller pixel count be less Mhz? Maybe my ModeLine is wrong somehow. I used GTF to create it.

hey thanks!
that modeline works now, but the image is stretched. How/what app did you compute that smpte 274m modeline with? gtf's modeline gave me a the same xy@hz but the pixel clock is much higher - weird.

I think I'm getting closer. I just want black bars on top and bottom, instead of stretching the display vertically. here's some clues from the xorg.log, but not sure how to get it to show me black bars instead of stretching.

By just reading the 274m document and putting the numbers found in there into a modeline. Any calculations done by hand.
I have calculated those when I connected my HDTV to a videocard quite some time ago and have pasted those modelines in threads here many times.

It sometimes is tough to make the nvidia driver do what you want. In the old days the XF86 server just took your modeline and loaded the values into some registers, resulting in a picture or garbage. It only checked H and V frequencies because back then a monitor could be destroyed by wrong frequencies.
Today there is an endless list of checks that make a carefully calculated modeline be "rejected", or when it is accepted assumptions are made that are not necessarily true.
Fortunately there still are options that enable working around this, but it has become more complicated.